forwarded ref of material-ui component is always null

I'am currently working on a navbar with a drawer element from the material-ui libary.

I want to forward the <Drawer> Component to the parent navbar, which should let me call the toggleDrawer function of my NavDrawer component. I used the forwardRef function from the react libary but my ref ist always null.

The parent component

function ParentComponent() {
    const drawerRef = useRef<DrawerHandle>(null);
    
    const toggleDrawer = () => {
        //  drawerRef.current is null >:(
        drawerRef.current?.toggleDrawer(true)
    };

    return (
        <>
            <AppBar position={"sticky"}>
                <Button onClick={toggleDrawer} />     
            </AppBar>
            <NavigationDrawer open={false} ref={drawerRef}/>
        </>
    );
}

and the forwarded drawer component

import React, {forwardRef, useState} from 'react';
import {Drawer} from "@mui/material";

type Props = {
    open: boolean
};

export type DrawerHandle = {
    alterToggle: () => void
}

const NavigationDrawer = forwardRef<DrawerHandle, Props>((props, ref) => {

    const [isOpen, setIsOpen] = useState(props.open)

    const toggleDrawer =
        (open: boolean) =>
            (event: React.KeyboardEvent | React.MouseEvent) => {
                if (
                    event.type === 'keydown' &&
                    ((event as React.KeyboardEvent).key === 'Tab' ||
                        (event as React.KeyboardEvent).key === 'Shift')
                ) {
                    return;
                }
                setIsOpen(open)
            };

    return (
        <Drawer
            ref={ref}
            anchor={"left"}
            open={isOpen}
            onClose={toggleDrawer(false)}
        >
            <p>Item1</p>
            <p>Item2</p>
        </Drawer>
    );
})

I cant wrap my head around the issue here, maybe its type related but than the ref object should be an wrongly typed object but not null.

You don't have to pass ref to the Drawer since you don't need access to it's properties. All you need is just imperativeHandle to return the handler to the parent.

// in NavDrawer

useImperativeHandle(ref,
  () => ({
     toggleDrawer,
  }),
[]);

Then the ref.current object in ParentComponent will contain toggleDrawer method.